Tubular construction



Sept. 3, 1940. l. J. NVAK TUBULAR CONSTRUCTION Filed uw 8' 1937.

Patented Sept. 3, 1940 [PATENT OFFICE TUBULAR CONSTRUCTION Izador J.Novak, Trumbull, Conn., assignor to Raybestos-Manhattan, Inc.,Bridgeport, Conn., `a corporation of New Jersey Application December 8,1937, Serial No. 178,682

4 Claims.

This invention pertains to an improved fibre Yboard tube construction orcompositionsuitable for such use.

, The object of this invention is to form an im- 5 proved nbre boardconstruction from which containers such as mailing or packing tubes maybe formed and which will have great rigidity and a high crushingstrength. I Another object is to produce a fibre board compositionsuitable for the formation'of mailing and shipping tubes and covers forcarrying fabrics and paper, can bodies, and the like, of cheap and lowgrade materials which have lhitherto not been deemed satisfactory forsuch construction as not l5 having the ability to provide strength andrigidity necessary for such constructions.v

Other objects and advantages will be apparent from the followingspecification and drawing, wherein, A

Fig. 1 is a perspective view o f a conventional mailing tube, and v Fig.2 is a perspective view of a tube such as that shown in Fig. 1, thehelical windings thereof being partially separated.

tulllg. 3 is a perspective view of a straight wound Referring to thedrawing, I0 indicates a conventional mailing tube fgrned in the usualmanner, that is, of strips of'iibre-board wound heli- A cally. Forexample, asshown in Fig. 2, two strips of fibre board are woundhelically in opposite directions, the strip I2. forming the inner helixand the strip |`I wound over it helically in the opposite direction.` Asthe fibres of the strip lie longitudi- 3; nally thereof in the usualformation of paper, by forming helical windings, the fibres are causedto lie obliquely to the longitudinal axis of the tube and bysuperimposing oppositely wound helices the fibres are caused to cross sothat the construction 40 of the tube is given a maximum strength and'rigidity against deformation of the tube or crushing. Straight woundtubes I4 as shown in Fig. 3 also may be made where the sheet is woundupon a mandrel with a suitable adhesive between the 45 layers orconvolutions. Another form of conventional tube winding is to windstrips helically in the same direction, with, however, superimposedlayers being in staggered relation, so that each successive layers isformed with the strip overlying 50 the abutting edges of theconvolutions of a lower strip layer.

Heretofore, in order to obtain maximum or required strength in a fibreboard subjected to uses such as the mailing tube construction hereincon- 65 templated, use has been made of fibres, stiff and rigid inthemselves, as for example, kraft, chestnut chip (tan bark) land thelike, to form kraft or chestnut board which now goes into theconstruction of the stiifest and strongest grade of tubes for thepurposes mentioned. ,While this 5 construction or other bre use issatisfactory, 1t

' into the pulp mix from which the board is to be formed, or added bythe wet web or dry web '20 saturation processes or in any other suitableor conventional manner so that a residual solids content of 10% to 15%of sodium silicate by weight relative to the bre is obtained, and whichI have found to be the most satisfactory composition. 25

In finishing the sheet or board a small amount of moisture may beretained to facilitate the handling, shaping or winding. -The silicatedboard thus formed in addition to being Waterproof has great strength andrigidity which renders it high- 30 1y desirable for the construction ofcontainers, and especially containers in tubular form wherein thegreatest requirement is that a stiff tube be maintained which willresist deformation and crushing.

While I have shown and described the construction of a' helically woundtube made of selected fibre-board, it Will readily be seen that due tothe strong bond or matrix formed between the fibres by means of thesodium silicate, tubes can 40 be formed of one or more layers of mysilicated board without winding strips in helical form. That is, thetubes can be formed by bringing together the edges of a suitable widthof board and sealing them in the form of a tube, or, the tube can beformed by forming several convolutions in a straight wound manner. Itwill also be seen f that due to the great rigidity and crushing ystrength obtained by using silicated fibres as herein -set forth, thecomposition will readily adapt itself to the forming of various shapessuch as bottles, bowls, vases, etc., or other articles by afibre-molding process, and it will therefore be seen that my compositionwill readily adapt itself for luse in-many fields and arts whereinmaterials heretofore constructed of expensive bres can now be producedby cheap and economical methods by the use of inexpensive bres whereinthere has been incorporated sodium silicate, to produce products havingcrushing strength and form retention properties to an extent which hashitherto been unattainable with similar rubstances.

I claim as my invention:

1. A tubular body having a relatively high crushing strength and adaptedto retain its tubular form and being substantially Waterproof, the saidbody being formed of sheeted fiber boards comprising low grade fibresand a binding agent therefor comprising 10% to 15% sodium silicate bydry weight of said bres.

2. An annular elongated body having walls :formed of relatively thinfelted brous material adapted to retain its form being substantiallywaterproof and having a high crushing strength, the said `felted fibrousmaterial comprising sheeted low grade pulp, and a binder thereforcomprising sodium silicate having a residual solid content of 10% to 15%by dry weight of said bres.

3. The method of forming a. waterproof tubu lar construction having ahigh crushing strength which comprises forming a fibrous board of lowgrade pulp material, incorporating therewith sodium silicate to yield aresidual sodium silicate content of 10% to 15% by weight of the dryfibre content of said board, and convolutely Winding the resultant boardin the form of tubes.

